The invention relates generally to a storage medium cartridge transport mechanism and more precisely to a storage medium cartridge adapted to cooperate with a storage medium cartridge gripping assembly.
Storage medium cartridges, such as tape cartridges or magneto-optical cartridges, have proven to be an efficient and effective means for storing data. Storage medium libraries utilize a plurality of storage medium cartridges as well as a number of storage medium drives for writing and reading data to or from the cartridges. The storage medium drives, for example, can be magnetic tape drives, magneto-optical drives, or a combination of both.
Storage medium cartridges employed within a library system are typically positioned within a number of removable cartridge magazines. Each magazine includes a plurality of magazine slots which contain the cartridges. The magazines are arranged within the library system to form an array of storage medium cartridges. Storage medium drives employed within the library system are generally positioned opposite the array of storage medium cartridges. A cartridge transport mechanism positioned between the array of cartridges and the drives moves the cartridges back and forth between the drives and the slots defined on the cartridge magazines.
The cartridge transport mechanism generally includes a cartridge gripper assembly positioned on an elevator mechanism. Typical cartridge gripper assemblies include a pair of cartridge gripping fingers that engage and securely hold a cartridge during transport. One example of a conventional cartridge gripper assembly that includes a pair of gripping fingers is shown in U.S. Pat. No. 5,691,859. This patent discloses a cartridge gripper assembly for moving a selected data cartridge between a tape drive and a tape cartridge magazine. The front bezel of the magnetic tape drive has both a gripper-tripping projection and two gripper spreading cam members. The two cam members cause the pair of gripper fingers of the cartridge gripper to spread apart when the gripper assembly travels toward the bezel. The gripper tripping projection abuts and snaps closed finger linkages which close the gripper fingers of the gripper assembly when the gripper assembly engages a cartridge. A pair of notches, formed on the exterior surface of the cartridge housing where the gripper fingers engage the cartridge, form a non-slip contact surface for the gripper fingers. In transporting a cartridge from a tape drive to a slot in the cartridge magazine, the elevator containing the gripping assembly is positioned adjacent to the drive containing the tape cartridge. The gripping mechanism moves toward the drive, actuating the gripping assembly, and causing the gripping assembly to engage the cartridge. The gripper fingers engage with the notches defined on the cartridge surface. The gripper assembly then moves away from the drive to extract the cartridge from the tape drive. The elevator mechanism containing the gripper assembly and cartridge is then moved to a position adjacent to the selected magazine slot. The gripping assembly and the cartridge then move into the magazine slot. At this point, a plunger defined on the gripping assembly is actuated as the cartridge inserts into the magazine slot and the cartridge is released.
One problem with the above described cartridge gripper, as well as with other similarly designed grippers, is that the gripper itself must be actuated by the gripper spreading cams and gripper-tripping projection defined on the front bezel of the tape drive. This gripper mechanism cannot be employed in tape library systems whose tape drives do not have these gripper spreading cams and gripper-tripping projection. Additionally, storage medium cartridges can have a substantially convex frontal portion that is not receptive to being engaged by the two-finger gripper as described above. When the convex frontal portion of a cartridge engages the two-finger gripper, the gripper fingers can snap on to the cartridge without engaging the pair of notches defined on the cartridge. As a result, the two-finger gripper can drop the cartridge.
Another drawback of the above described cartridge gripper assembly is that it requires numerous parts and is relatively complex and difficult to assemble.
Thus, a hitherto unsolved need has remained for a cartridge gripper assembly that can be employed within a storage medium library for moving cartridges that does not require gripper spreading cams and gripper-tripping projections.
A first embodiment of the present invention comprises both a storage medium cartridge that is adapted for use with a cartridge gripping assembly and a cartridge gripping assembly.
The storage medium cartridge includes a substantially rectangular housing having an aperture formed on the exterior of the housing. The aperture is dimensioned to be receptive to a cartridge gripping assembly. The cartridge gripping assembly includes a cartridge gripping mechanism. The cartridge gripping mechanism includes a first end and a second end. The first end of the gripping mechanism is dimensioned to engage the aperture defined on the cartridge and the second end of the gripping mechanism is dimensioned for coupling with a first end of a robotic arm. The first end of the gripping mechanism includes first and second ramped portions. The first ramped portion is defined on a first plane and the second ramped portion is defined on a second plane, where the first plane and the second plane are parallel with respect to each other. The second ramped portion is positioned directly over and is integral with the first ramped portion. However the second ramped portion has a narrower crosswise or transverse width than the first ramped portion. The longitudinal edges of the second ramped portion are undercut such as to form a pair of longitudinal grooves between the longitudinal edges of the second ramped portion and the planar surface of the first ramped portion.
The gripping mechanism further includes a central arm having a first end and a second end. The first end is pivotably connected to a slide portion via a hinge. The slide portion is a wedge shaped component that is dimensioned to slidably engage the grooves formed on the first and second ramped portions. The second end of the central arm is coupled to an actuation means via another hinge. One preferred actuation means is an air cylinder. Actuating the air cylinder results in the central arm moving back and forth along a longitudinal axis, where such motion is further translated to the slide portion for moving the slide portion up and down the ramped portions.
During operation, the first end of the gripping mechanism is positioned in the aperture defined on the storage medium cartridge. Then the actuation means associated with the gripping mechanism is actuated to move the front edge of the slide portion from a first position defined at the bottom region of the ramped portions to a second position defined at the top region of the ramped portions. In moving the front edge of the slide portion from the first position to the second position, the effective height of the combination of the ramped portions and the slide portion increases. This expansion of the ramped portions and slide portion presses the combination against the inner circumferential walls of the aperture and frictionally secures the cartridge to the gripping mechanism. Reversing the actuation means allows the slide portion to return back to its original position and disengages the cartridge engagement mechanism from the aperture and releases the cartridge.
These and advantages, aspects and features of the present invention will be more fully understood and appreciated upon consideration of the following detailed description of a preferred embodiment, presented in conjunction with the accompanying drawings.